shoney.arickathil
0df9b4fe31
- Modules: `use`/`pub`, directory-as-module, per-module symbol resolution (a
flat first-wins merge silently ran the wrong `pub fn` body), six reserved
stdlib namespaces typed UNKNOWN-BUT-RESERVED.
- Surface: `and`/`or` (own precedence tier, short-circuit, Bool-only), `${}`
interpolation desugared at parse time, `const`, break/continue with
drop-correct exits, do-while, inline-fn rejection.
- switch expr/stmt: required `default` over scalars/Text, arm unification,
EQ/EQS+JZ lowering, per-arm drop scopes with N-way JOIN-DROP; `default`
sorted last by a shared lowering order (textual order made arms dead).
- typedef records: structural, same shape = one class entry; `?name: T`
nullable-by-shape; emit_ctor fills omitted defaults; `type` as field name.
- Enum variants: all-bare unions = int ordinals; any-payload = one class
entry per variant, tag IS the header class_id (no header field, no format
bump); exhaustive switch without `default`; arity checked both directions.
- Payload escape modeled as move-out (pointer-kind fields only — a scalar
escape is a copy); caller reaps owned heap temps passed by borrow: two
unbounded LSan-blind leaks, 10.5 MB -> 1.5 MB flat over 300k iterations.
- Fixed en route, each with a RED repro: dead E209 builtin-arg check and
`int_to_text` missing from both types.ml builtin tables (both segfaulted
wovm), multi-file phantom double-report, emit_ctor's field temp clobbering
dst in tail position (pre-existing), warnings swallowed without an error.
- Two fenced VM builtins: `int_to_text` (13), `variant_tag` (14).
- 14+565 unit (was 14+401), corpus 71 (was 32) plain and under wovm_asan,
wovm-test + cli_smoke green. Log-watcher 307 -> 93 diagnostics (85 E101 /
4 E207 / 1 E208 / 3 W202); the 5 non-E101 residuals await Task 7 grammar.
220 lines
11 KiB
Markdown
220 lines
11 KiB
Markdown
# Milestone-1 source surface the emitter lowers — normative reference
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> What a `.wo` program may say and have `woc` produce bytecode for.
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> The `.wob` format doc ([`00-wob-format.md`](00-wob-format.md)) names the
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> BUILTIN *ids*; this names their **source spellings** and the handful of
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> rules that have no other home. Landed with the emitter
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> (`compiler/src/emit.ml`, plan 3 task 1). Diagnostics referenced here are
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> catalogued in [`01-error-catalog.md`](01-error-catalog.md).
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>
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> Anything on this page is a contract for corpus fixtures and for every
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> later sub-project's `.wo` code — not an emitter implementation detail.
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## Builtins
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Containers and runtime services are free functions, never methods. Each
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maps to one `BUILTIN` id of the format doc.
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| source | `.wob` builtin | arity | meaning |
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| --- | --- | --- | --- |
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| `now()` | `now` | 0 | wall-clock milliseconds (`Int`) |
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| `print(t)` | `print` | 1 | a `Text`, newline-terminated |
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| `print_int(n)` | `print_int` | 1 | an `Int`, newline-terminated |
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| `words(t)` | `words` | 1 | whitespace token count of a `Text` |
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| `multi_new()` | `multi_new` | 0 | a fresh `multi T` — see the destination rule below |
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| `map_new()` | `map_new` | 0 | a fresh `map<K, V>` — see the destination rule below |
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| `push(m, v)` | `multi_push` | 2 | append to a `multi` |
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| `count(c)` | `count` | 1 | length of a `multi` or a `map` |
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| `latest(m)` | `latest` | 1 | last element of a `multi` (traps `BOUNDS` when empty) |
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| `get(c, k)` | `multi_get` / `map_get` | 2 | element by index, or value by key (a missing key traps `KEY`) |
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| `set(m, k, v)` | `map_set` | 3 | insert or replace in a `map` |
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| `has(m, k)` | `map_has` | 2 | `1`/`0` |
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| `int_to_text(n)` | `int_to_text` | 1 | decimal rendering of an `Int`, as a fresh owned `Text` — haxe-parity Task 2's one fenced VM addition, the type-directed half of string interpolation (below); also directly callable |
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`get`, `set`, `push`, `count` and `has` resolve on the container they are
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given, so one source name covers the `multi` and `map` ids the runtime
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keeps apart.
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**Sugar.** `c[i]` is exactly `get(c, i)` and `m[k] = v` is exactly
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`set(m, k, v)`. There is no element *write* into a `multi` — v1 has
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`multi_push` and `multi_get` and no element store — so `m[i] = v` on a
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`multi` is `WO-E403`.
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**Shadowing.** A user-declared free `fn` of the same name always wins. A
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declared name is never silently replaced by a builtin.
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**`push` and `@gc` elements.** `push(m, v)`'s value argument is never a
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resolved callee parameter (`push` has no declared signature), so the
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owner pass's ordinary Take-gated transfer never reaches it; a `@gc` value
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pushed into a `multi` is special-cased in `owner.ml`'s `analyze_call`
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(the value escapes into the container exactly like a ctor field, RC_INC
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included) specifically so a `multi`-mediated `@gc` cycle can be built
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and later collected (`tests/corpus/gc/`, plan 3 task 5). **`set(m, k, v)`
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has no equivalent special case** — a `@gc` key or value handed to `set`
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is not retained, so a `map<_, SomeGcClass>` (or a `@gc`-keyed map) built
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this way will under-count its element's refcount and the collector will
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free it while the map still points at it. Nothing in the corpus
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exercises this yet; treat it as an open gap, not a proven-safe pattern,
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until `set` gets the same fix `push` did.
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## A fresh container needs a destination of declared type
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`multi_new()` and `map_new()` carry their element (and key/value) kinds as
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an instruction immediate, and those kinds **are** the container's drop
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plan at runtime (`runtime/src/gc.c`). They cannot be guessed: assuming
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`SCALAR` for a `multi Item` leaks every element, and for a
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`map<Text, _>` leaks every key. Milestone-1 `let` has no container type
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annotation — its optional annotation is a bare identifier — so a fresh
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container must be created where its type is declared:
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```wo
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class Store {
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items: multi Item
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by_name: map<Text, Int>
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}
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fn main() {
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let s = Store { items: multi_new(), by_name: map_new() } -- kinds from the fields
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push(s.items, Item { n: 7 })
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set(s.by_name, "seven", 7)
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}
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```
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A bare `let m = map_new()` is `WO-E403`, reported at the creation site.
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The same rule applies to a `take`/`mut` parameter of declared container
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type, which is also a typed destination.
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## Calls
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- Argument count must match the callee's parameter count (`WO-E403`).
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Nothing upstream checks arity — `types.ml` declares `WO-E203` and never
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raises it — and a mismatched call reserves a register window the callee
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does not read, which the loader rejects outright.
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- A method is called as `receiver.method(args)`. When the receiver's
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declared type is an **interface**, the call is dispatched by vtable
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(`ICALL`); satisfaction is structural (same method name, same parameter
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count), Go-style, with no `implements` keyword.
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- `self` occupies the callee's `r0`, so a method's argument count is
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`1 + parameters`.
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## Modules (haxe-parity Task 1)
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A `.wo` file's **module is its directory** — no manifest, no declared
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module name. Every file sharing a directory sees every other same-
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directory file's declarations unconditionally (Task 8's existing
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multi-file discovery, unchanged); a name declared in a *different*
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directory needs `use` to become visible at all, and even then only if
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it is marked `pub`.
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- **`pub`** on a top-level `class`/`type`/`interface`/`fn` exports it
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outside its own module. Default is private-to-module — visible to
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every file in the same directory, invisible to every other module
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regardless of `use` (`WO-E217` if referenced anyway). `pub` on a
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class/interface method, or the `pub(read)` field-accessor marker
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(Haxe's `(default, null)`), is a different, later feature — not this
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one.
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- **`use fs`** (a bare, single-segment name) is a **reserved stdlib
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namespace**: exactly `fs`, `proc`, `net`, `time`, `json`, `env`, no
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others, and always stdlib even if a same-named project directory
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exists. A call through one (`fs.stat(...)`) typechecks as
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UNKNOWN-BUT-RESERVED — no E207/E225/arity check, since the six
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namespaces' members arrive in plan 9 — and is `WO-E406` only if such
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a call survives all the way to emission; an unused `use fs` compiles
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clean (modulo `WO-W202`, below).
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- **`use shared/util`** (slash-separated segments) is **project-
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relative**: it must name a directory this program's own discovery
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actually finds, or `WO-E216`. The alias a call site uses is always
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the path's *last* segment (`util.fn(...)`, not `shared.fn(...)`).
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- **Resolution order** for a bare (unqualified) name: this file's own
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module, unconditionally; then every `use`d module's `pub` surface. If
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more than one used module exports the same `pub` name, that is
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`WO-E218` — collisions diagnose rather than silently pick a winner.
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A qualified reference (`alias.name(...)`) skips straight to its
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named module; `WO-E217` if `name` exists there but isn't `pub`.
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- A `use` clause never referenced (bare or qualified) anywhere in its
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own file is `WO-W202` — a warning, so it does not fail the build.
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## Program entry
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The entry point is the **zero-argument free `fn main`**. A `main` that
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takes parameters is not an entry (the format's own rule is a zero-argument
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free fn), and `wovm` will report `module has no entry method`.
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## Operators with no dedicated opcode
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Lowered by the emitter, not added to the format:
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| source | lowering |
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| --- | --- |
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| `a % b` | `a - (a / b) * b` — exact for the VM's truncating `DIV`, which traps on `0` and on `INT64_MIN / -1`, both correct for `%` too |
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| `a != b` | `(a == b) == 0` |
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| `a > b`, `a >= b` | `LT` / `LE` with the operands swapped |
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| `a == b` on `Text` | `EQS` (content equality); `EQ` otherwise |
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| `a .. b` | `CONCAT` — `+` is arithmetic only, never string addition |
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| `a and b` | evaluate `a`; `JZ` past evaluating `b` (result stays `a`'s value); else evaluate `b` into the same register (haxe-parity Task 2) |
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| `a or b` | evaluate `a`; `JZ` + `JMP` past evaluating `b` when `a` is already true; else evaluate `b` (haxe-parity Task 2) |
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## Not lowerable in milestone 1
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Each is `WO-E403` at the offending site, never invented bytecode:
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- an element write into a `multi` (no element-store instruction);
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- `for` over a `map` (v1 exposes no key enumeration);
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- a name that is neither a local, a parameter, `self`, a declared `fn`,
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nor a builtin;
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- a field or method on a type that is not a declared class — including a
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class named only inside `multi T` / `ref T`, which `types.ml`'s
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unknown-type check (`WO-E225`) does not look inside.
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- `break`/`continue` outside any loop (haxe-parity Task 2) — nothing
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upstream tracks loop nesting to reject it earlier, so the emitter's
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own "no legal jump target" gate is the only one.
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- interpolating (`"${expr}"`) a value that is neither `Text` nor `Int`
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(haxe-parity Task 2) — the brief's own scope; a class, `multi`, `map`,
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or other scalar has no defined textification here.
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## Small control surface (haxe-parity Task 2)
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`break`/`continue`/`do...while`, `const`, `and`/`or`, and string
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interpolation — the haxe keyword verdict table's low-risk batch, added
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2026-08-11.
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- **`break`/`continue`** reuse the owner pass's own `return`-drop
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machinery, bounded to the nearest enclosing loop instead of the whole
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function: an owned value still alive in the loop body is dropped at
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the `break`/`continue` site itself, not left to leak (proven under
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ASan, `tests/corpus/run/lang-break-owned-drop/`). `continue`'s actual
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jump target depends on loop shape — `while`'s own condition check,
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`for`'s increment step, or `do...while`'s condition check — but the
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drop-set computation is identical either way.
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- **`do { body } while cond`** — the body always runs at least once;
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lowered onto the same `JZ`/`JMP` pair `while`/`for` already use, just
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reordered.
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- **`const NAME = <literal>`** (top-level, or bare — no `static` —
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class-level) is resolved entirely by `parser.ml`, before typecheck
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ever runs: every unshadowed reference is replaced by the literal it
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names, so nothing downstream (types/owner/emit) has any const-specific
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code at all. A local/parameter/`self` of the same name always shadows
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it. `static const` is Task 7's own syntax (`static`), not recognized
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here.
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- **`and`/`or`** are real keywords (never `&&`/`||`), one precedence
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level below comparison (`or` loosest, then `and`, then comparison —
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so `a == 1 and b == 2` needs no parens). `Bool`-typed operands only,
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no truthiness: a confidently-non-`Bool` operand is `WO-E201`. Short-
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circuit, lowered to compare-and-jump above — no new opcode.
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- **String interpolation** (`"${expr}"`) desugars at parse time to a
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`..` (`Concat`) chain of text segments and embedded expressions; each
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embedded expression's *textification* is decided at emit time, once
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its type is known: `Text` passes through untouched, `Int` is wrapped
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in `int_to_text` (above), anything else is `WO-E403` (see "Not
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lowerable in milestone 1"). `\$` is a literal `$` (so `\${x}` stays
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literal, never interpolates); a lone `$` not followed by `{` is also
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literal, unconditionally.
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## `?T`
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A nullable field stores exactly what `T` stores and spells nil as `0`.
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The v1 format has no kind byte for it (field kinds run `0..5`; the loader
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rejects `6`), and it needs none: every per-kind drop plan already ignores
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a zero slot. `?T`'s field kind is therefore `T`'s. Note the consequence
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for `@gc`: `?SomeGcClass` is a `GCREF` field like any other, so it
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participates in refcounting and cycle detection normally.
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